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My PCB has drill holes in it as it needs to be screwed onto a case. Since some of the components too close to the screws were shorting, I moved components around to solve the problem.

This resulted in one airwire where one side of the resistor which was to be connected to ground became unconnected affecting the functionality of the LED on my board.

To fix this problem I connected that one airwire to ground and checked for any other errors and airwires. Finiding none and passing the 4pcb design rule check online I went ahead and got a few hundred boards manufactured.

Now after assembling them I see that this small change screwed up the functionality of the entire board. I am baffled and confused as to how a small change of connecting the resistor airwire to the nearest ground via could cause this?

Any suggestions on why this could be happening and how I could solve this would be helpful.

Thanks

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    \$\begingroup\$ A schematic and images/gerbers of the PCBs before and after would help \$\endgroup\$ Commented Nov 2, 2011 at 17:43
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    \$\begingroup\$ You probably changed something else while moving the components around. \$\endgroup\$
    – Majenko
    Commented Nov 2, 2011 at 17:58
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    \$\begingroup\$ You made a change and went straight to production without checking it!!? \$\endgroup\$ Commented Nov 2, 2011 at 19:23
  • \$\begingroup\$ It might help if you mentioned which PCB software you are using \$\endgroup\$ Commented Nov 3, 2011 at 0:51
  • \$\begingroup\$ @OlinLathrop This board had gone through a bunch of internal testing before and I know its my bad to have assumed that one small change will not cause the entire thing to break. \$\endgroup\$ Commented Nov 3, 2011 at 16:07

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You could try creating a "Visual Diff" of your (before and after) design and gerber files. See if anything "jumps out" at you as "the problem." This article describes how to do it.

Also, my personal experience has been that the circumstances where you can confidently get away with going straight to manufacture after a change to a PCB design are rare. For me, it's almost always worthwhile to spend the $20 and wait the extra couple of weeks to have a prototype manufactured before going to a production quantity.

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    \$\begingroup\$ +1 for always getting some prototype boards made before going into production after making a change. \$\endgroup\$
    – tcrosley
    Commented Nov 2, 2011 at 18:55
  • \$\begingroup\$ I forgot one main piece of information here....the original board had a thickness of .031 and the new board has a thickness of .063 .... could that be the possible cause of this issue? \$\endgroup\$ Commented Nov 3, 2011 at 16:12
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    \$\begingroup\$ depends how sensitive your application is to capacitance related issues (e.g. if there is high speed signalling)... \$\endgroup\$
    – vicatcu
    Commented Nov 4, 2011 at 17:23

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